Positron emission tomography (PET) has been successfully used in the imaging of various cancers. In this retrospective study, we examined clinical utility of PET in the imaging of liver metastasis from colorectal cancer. Results of PET were compared with those of ultrasonography (US) and contrast-enhanced computer tomography (CT) in 11 liver metastases seen in eight patients with recurrent colorectal cancer. The detection rates were 73% (8 of 11 metastases) by US, 73% (8 of 11 metastases) by CT, and 82% (9 of 11 metastases) by PET. PET correctly identified US-negative and CT-negative liver metastases. However, PET was negative in one patient with minute metastases. The findings in our preliminary study were in agreement with those of previous reports. A prospective study is warranted to determine the optimum role of PET in the management of patients with colorectal liver metastasis.